More than 87,000 Americans died of drug overdoses over the 12-month period that ended in September, according to preliminary federal data, eclipsing the toll from any year since the opioid epidemic began in the 1990s. The surge represents an increasingly urgent public health crisis, one that has drawn less attention and fewer resources while the nation has battled the coronavirus pandemic. Deaths from overdoses started rising again in the months leading up to the coronavirus pandemic — after dropping slightly in 2018 for the first time in decades — and it is hard to gauge just how closely the two phenomena are linked. But the pandemic unquestionably exacerbated the trend, which grew much worse last spring.